An anagram is a word or phrase made by rearranging every letter of another word or phrase, with each letter used exactly once.
That last part is the whole test: every letter, used once. “Angered” and “enraged” are anagrams because both use one each of a, d, e (twice), g, n and r. “Angered” and “anger” are not, since the second drops two letters rather than reordering all of them.
Because the letters themselves never change, only their order, an anagram keeps the same length and the same letter tally as the word it came from. Sort those letters alphabetically and you get a fingerprint every anagram of that word shares - which is precisely the trick that lets a computer find them instantly rather than testing every possible arrangement.
For the fuller academic treatment, including edge cases around punctuation, capitalisation and multi-word phrases, see Britannica's entry on the term.
A short history
The word “anagram” entered English in 1589, borrowed from the Greek for rearranging letters. The habit it describes is older than the word: Renaissance scientists used anagrams to stake a claim on a discovery without revealing it outright, and crossword setters have leaned on the same mechanic ever since the puzzle form itself arrived.
The word itself entered the language in 1589, borrowed via the Greek for "letters again", built from ana- ("back" or "again") and gramma ("letter"). The practice it names predates the word by a good deal longer.
The best-documented historical case is scientific rather than literary. Galileo announced his discovery of Saturn's rings as a scrambled Latin sentence in 1610, sending the anagram to a rival astronomer ahead of publishing the plaintext. If a competitor made the same discovery in the meantime, Galileo could unscramble his own anagram and prove he had got there first, all without tipping anyone off by publishing openly.
Crossword setters lean on anagrams constantly, and so do pen names - the habit of hiding one name inside another arrangement of letters is one of the oldest party tricks the form has.
Anagrams across languages
An anagram is defined against one language's own dictionary, so the same source letters produce entirely different valid anagrams from language to language. These examples are computed live from the actual wordlists this site ships, never asserted from memory.
The letters a, c, e, n, r and t rearrange into the French words carnet (notebook) and nectar (nectar) - both real, dictionary-checkable words sharing one set of letters, the same relationship "angered" and "enraged" have in English.
German does better with the same six letters in a different combination: a, e, k, n, r and t produce karten (cards), tanker (tanker) and nektar (nectar) - three real nouns from one letter set, one more than the English or French equivalents manage at the same length.
What an anagram is not
- A palindrome
- reads identically forwards and backwards, such as “rotator”. Nothing gets rearranged at all.
- A cipher
- swaps letters for other letters or symbols. An anagram swaps nothing - it only reshuffles what is already there.
- A subset of letters
- such as “angel” taken from “angered” is a shorter word built from part of the original, not an anagram, because letters were left out.
- An antigram
- is an anagram whose new meaning runs against the original - “funeral” and “real fun” is the classic pairing.
Anagrams from this wordlist
Everything below was worked out from the dictionary this site actually runs on, so each set is a genuine, checkable anagram rather than a repeated textbook example.
- alger - elgar, glare, lager, large, regal
- darin - dinar, drain, indra, nadir, randi
- ergo - goer, gore, ogre, oreg, roeg
- leapt - lepta, patel, petal, plate, pleat
- least - slate, stael, stale, steal, tesla
- abel - able, bale, bela, elba
- aden - dane, dean, dena, edna
- adorn - drano, norad, radon, ronda
Questions people actually ask
Does every letter have to be used?
Yes - it is the definition. A word built from only some of the letters is a subset rather than a true anagram, though most word games are happy to accept those too, which is why this solver returns both and lets you filter down to strict anagrams if you want.
What is the quickest way to work one out by hand?
Put the letters in alphabetical order to get a fingerprint, then hunt for dictionary words sharing that same fingerprint. That is exactly the method this solver runs, which is why it answers immediately rather than working through every possible arrangement.
Can more than one word be involved?
Yes. A phrase anagram rearranges the letters of an entire phrase and simply ignores spaces and punctuation while doing it. “A gentleman” and “Elegant man” is a well-worn example.
Do most words have anagrams?
No - most have none at all. A small number have quite a few: four or more genuine English words sharing one set of letters is unusual without being freakishly rare, and the richest examples on this page are drawn from exactly those cases.
Try the method above on your own letters in the solver at the top of this page, or work through the German example yourself before checking it against the dictionary.